JPS637915B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an articulated robot having an articulated arm means on a base, in particular a rotation range that rotates back and forth around a standing posture and a rotation range that rotates up and down. It is an object of the present invention to provide an articulated robot equipped with a spring balancer that effectively acts on a first arm of the articulated arm means that can rotate continuously over a period of time.

As this type of articulated robot with a spring balancer, a robot disclosed in Japanese Patent Application Laid-open No. 119391/1983 is known. In this conventional robot, the wire pulled by the spring balancer is directly connected to the first arm of the articulated arm means, so the stroke of the piston in the spring balancer corresponds to the vertical movement range of the first arm. In order to absorb the slack of the wire when the first arm moves from the vertical movement range to the front and back rotation range, the second spring is attached in the wire tension direction. It uses a special spring balancer with a built-in secondary piston. As a result, the overall length of the spring balancer becomes long, and the structure is complicated, resulting in high cost.

The present invention proposes an articulated robot with a spring balancer that can solve the above-mentioned conventional problems.

Hereinafter, one embodiment of the present invention will be described based on the attached illustrative drawings. In FIG. 1, 1 is an installation base, 2 is a rotating base that rotates around a vertical axis 3,
Reference numeral 4 denotes an articulated arm means provided on the pivot base 2. This articulated arm means 4 includes a first arm 6 whose inner end is rotatably supported around a horizontal axis 5 with respect to the pivot base 2, and an outer end of the first arm 6 on one side. A second arm 8 is rotatably supported around a horizontal axis 7, and a horizontal axis 9 is provided at one side of the outer end of the second arm 8 (the side where the first arm 6 is located).
The wrist arm 10 is provided with a wrist body 12 that rotates around an axis 11 perpendicular to the horizontal axis 9. ing. Note that the horizontal axes 5, 7, and 9 are parallel to each other.

As shown in FIGS. 2 and 3, the rotating base 2
is rotatably supported by a bearing 13 while being fitted onto the upper end of the cylindrical installation base 1 .
14 is a rotating base driving motor, which is supported within the installation base 1 in a state concentric with the vertical axis 3;
A gear reducer 15 is provided on the upward output shaft 14a.
An input shaft 15a of a gear reducer (such as a harmonic reducer) is connected thereto, and an upward output shaft 15b of the gear reducer 15 is fixed to the base plate 2a of the rotating base 2. Reference numeral 16 denotes a motor supporting cylindrical body that stands upright within the installation base 1 and houses the motor 14, and a conical cylindrical member that is attached to the upper end of this cylinder 16 and houses the gear reducer 15. 17 connects the motor 1 via a bracket 18
4 is suspended, and the input/output shafts 15a, 15b of the gear reducer 15 are supported by bearings 19.

Therefore, the rotation of the output shaft 14a of the motor 14 is transmitted to the swing base 2 while being reduced by the gear reducer 15, and the rotation base 2 is rotated so that the vertical axis 3 is aligned with the installation base 1. It will be forced to rotate around you.

Reference numeral 20 denotes a first arm driving motor, which is installed on the base plate 2a in the rotating base 2 in a state close to the vertical axis 3. The output shaft 20a of the motor 20 is interlocked with a central input shaft 24a of a gear reduction device 24 via toothed belt wheels 21, 22 and a toothed belt 23.
and its outer fixing ring 24
b is supported by a bearing portion 25 protruding from the upper part of the swing base 2, and a ring-shaped output rotating body 24c is fixed to one side of the first arm 6.

Therefore, the rotation of the output shaft 20a of the motor 20 is transmitted to the central input shaft 24 of the gear reduction device 24 via the toothed belt wheels 21, 22 and the toothed belt 23.
a, and after being decelerated by this device 24, the first arm 6 is transmitted from the ring-shaped output rotating body 24c.
This causes the first arm 6 to rotate around the horizontal axis 5 with respect to the rotating base 2.

Reference numeral 26 denotes a wrist arm drive motor disposed concentrically with the horizontal axis 5, and is supported by the bearing portion 25 via a bracket 27 that covers the toothed belt pulley 22. This motor 26 includes a gear reducer (such as a harmonic reducer) 28 and a rotating shaft 29 connected to its output shaft 26a.
The endless chain 30 is driven through. The rotating shaft 29 is the central input shaft 24 of the gear reduction device 24.
a, and both ends are supported by the motor support bracket 27 and a central bearing part 31 protruding from the rotating base 2 so as to be located between the bifurcated inner ends of the first arm 6. One end is connected to the output rotating body 28a of the gear reducer 28. The endless chain 30 is stretched on one side of the first arm 6, and has a toothed ring 32 fixed to the inner end of the rotating shaft 29, and a second arm 8 as shown in FIGS. 4 and 5. It is suspended between the horizontal axis 7, which is the center of rotation of the gear, and the gear wheel 33, which is concentric with the horizontal axis 7. This tooth ring 33
is fixed to the second arm 8 so as to be concentric with the horizontal axis 7 and is rotatably supported by a cylindrical shaft 34 that protrudes toward the first arm 6 side. 35 is an endless chain stretched on one side of the second arm 8;
It is hung between 6 and 37. The tooth ring 36 is integrally formed with the tooth ring 33, and the tooth ring 37 is
It is fixed to a cylindrical shaft 38 which is fixed to the wrist arm 10 and supported by the outer end of the second arm 8 in a state concentric with the horizontal axis 9.

Therefore, the rotation of the output shaft 26a of the motor 26 is decelerated by the gear reducer 28.
Rotating shaft 29, tooth ring 32, endless chain 30, tooth ring 3
3, 36, the endless chain 35, and the toothed ring 37 to the cylindrical shaft 38, and the wrist arm 10 is rotated about the horizontal axis 9 relative to the second arm 8.

In FIG. 2, reference numeral 39 is a motor for driving the wrist main body, and a gear reducer (such as a harmonic reducer) 40 and a rotating shaft 4 are connected to its output shaft 39a.
1 to drive the endless chain 42. The rotating shaft 41 is concentric with the horizontal axis 5, which is the center of rotation of the first arm 6, and is supported at both ends by a bearing portion 43 projecting upward from the rotating base 2 and the central bearing portion 31. , the outer end is coupled to the output rotating body 40a of the gear reducer 40. Said motor 3
9 and the gear reducer 40 are supported by a bracket 44 fixed to the bearing portion 43 so as to be concentric with the horizontal axis 5. The end of the bifurcated inner end of the first arm 6 that loosely fits between the central bearing 31 and the bearing 25 is supported by the rotating shaft 29 via the gear reduction device 24 as described above. However, the end portion that loosely fits between the central bearing portion 31 and the bearing portion 43 is directly supported by the rotating shaft 41. The endless chain 42 is stretched on a side of the first arm 6 opposite to the side where the endless chain 30 is located, and is connected to the rotating shaft 41.
It is suspended between a toothed ring 45 fixed at , and a toothed wheel 46 which is concentric with the horizontal axis 7 as shown in FIGS. 4 and 5. This tooth ring 46 is connected to the cylinder shaft 3.
The rotary shaft 47 is fixed to the first arm side end portion of a rotating shaft 47 that is supported across the first arm 6 and the second arm 8 so as to pass through the interior of the rotary shaft 47 . 48 is an endless chain stretched on the opposite side of the second arm 8 from the side where the endless chain 35 is located, and is connected to the rotating shaft 47.
It is suspended between a toothed ring 49 fixed to the second arm side end of the cylinder and a toothed ring 51 fixed to one end of a rotating shaft 50 supported concentrically within the cylindrical shaft 38.
The rotating shaft 50 is the driving shaft 5 of the wrist main body 12.
2 through bevel gears 53 and 54.

Therefore, the rotation of the output shaft 39a of the motor 39 is reduced by the gear reducer 40, and
Rotating shaft 41, tooth ring 45, endless chain 42, tooth ring 4
6. The wrist main body 1 is transmitted to the wrist main body drive shaft 52 via the rotating shaft 47, the gear ring 49, the endless chain 48, the gear ring 51, the rotating shaft 50, and the bevel gears 53 and 54.
2 is rotated around the axis 11 with respect to the wrist arm 10.

In FIG. 3, 55 is a motor for driving the second arm, and when the first arm 6 rotates around the horizontal axis 5 to the lower limit position as shown in the figure, The first arm 6 is positioned almost directly above.
The output shaft 55a is located at the upper inner end of the horizontal axis 5.
It is installed parallel to the The output shaft 55a of this motor 55 is interlocked and connected to an intermediate rotating shaft 56 supported at an intermediate position of the first arm 6 via toothed belt wheels 57, 58 and a toothed belt 59. is the central input shaft 60a of the gear reduction gear 60 as shown in FIG.
are interlocked and connected via toothed belt wheels 61, 62 and a toothed belt 63. The gear reduction device 60 is supported inside the outer end of the first arm 6, with the rotating shaft 47 concentric with the horizontal axis 7 passing through the central input shaft 60a, and the outer fixing ring 60b is connected to the outer end of the first arm 6. The ring-shaped output rotary body 60c is fixed to one arm 6, and the ring-shaped output rotating body 60c is fixed to an enlarged diameter cylindrical portion 34a of a cylindrical shaft 34 fixed to the second arm 8 side.

Therefore, the rotation of the output shaft 55a of the motor 55 is transmitted to the intermediate rotating shaft 56 via the toothed belt wheels 57, 58 and the toothed belt 59, and further to the toothed belt wheels 61, 62 and the toothed belt 63. The signal is transmitted to the central input shaft 60a of the gear reduction device 60 through the gear reduction device 60, and after being decelerated by the device 60, the signal is transmitted to the cylindrical shaft 34 from the ring-shaped output rotating body 60c, and the second arm 8 connects to the first arm 6. It is rotated around the horizontal axis 7 relative to the horizontal axis 7.

In FIG. 3, reference numeral 64 is a spring balancer, which includes a cylinder 65 fixed substantially vertically to the rotating base 2, and a main coil spring 66 that is slidably installed inside the cylinder 65. A piston 67 that is biased downward, a rod 68 that projects upward from the piston 67,
It is composed of an auxiliary coil spring 69 that is compressed at the end of the upward stroke of the piston 67. A rotating ring 70 is rotatable around the horizontal axis 5, which is the center of rotation of the first arm 6, and is rotatable on the ring-shaped output rotating body 24c of the gear reduction gear 24, as shown in FIG. It is loosely fitted into the This rotary ring 70 has a chain guide 71 protruding from a part of a gear ring, and the other end of a chain 72, one end of which is locked to the upper end of this chain guide 71, is placed on this chain guide 71. While holding the chain 72 on the rod 68 of the spring balancer 64,
A long hole 73 formed concentrically in the rotating ring 70
As shown in FIG. 2, a pin 74 protruding from the side surface of the first arm 6 is loosely fitted inside. Then, the first arm 6 rotates in a rotation range R1 in the approximately front-back direction from the upper limit of movement position A, which is about 30 degrees backward from the vertical position, to the intermediate position B, which is about 60 degrees forward. When the rotation ring 70 is stopped at the return limit where the lower end of the chain guide 71 contacts the swivel base 2, as shown by the imaginary line, the pin 74 moves inside the elongated hole 73 from the position a. Rotation range r to position b
1, and when the first arm 6 rotates in the rotation range R2 in the approximately vertical direction from the intermediate position B to the approximately horizontal downward movement limit position C, the pin 74 moves in the elongated hole 73. The rotary ring 70 is rotated clockwise in the figure in the rotation range r2 from position b to position c, and the main coil spring 66 is rotated through the chain 72, rod 68, and piston 67. It is configured to be compressed.

Therefore, when the first arm 6 rotates within the rotation range R1 in the approximately longitudinal direction, the spring balancer 64 does not act, and the first arm 6 rotates within the rotation range R2 in the approximately vertical direction. Only when the main coil spring 66 of the spring balancer 64 is compressed in proportion to the downward rotation angle from the intermediate position B, the reaction force is a downward rotational force acting on the first arm 6 due to gravity. In other words, the load on the motor 20 that rotates the first arm 6 is reduced. It should be noted that when the first arm 6 is within the rotation range from slightly before reaching the lower movement limit position C to reaching the lower movement limit position C, that is, when the first arm 6 is in the rotation range due to gravity, the first arm 6
In a region where the downward rotational force acting on the first arm 6 is maximum, not only the main coil spring 66 but also the sub coil spring 69 are compressed, and the lifting force acting on the first arm 6 is increased.

According to the articulated robot configured as described above, the motor 14 is used to rotate the rotation base 2 around the vertical axis 3, and the motor 20 is used to rotate the first arm 6 around the horizontal axis. A rotational movement around the center 5, a rotational movement of the second arm 8 around the horizontal axis 7 caused by the motor 55, and a rotational movement around the horizontal axis 9 of the wrist arm 10 caused by the motor 26. , and the rotational movement around the axis 11 of the wrist body 12 performed by the motor 39, various robot hands attached to the wrist body 12 can be moved from any position to any other position. The robot hand can be moved along a route to perform the desired work.

As described above, according to the articulated robot of the present invention,
When the first arm 6 is in a position where the downward rotational force acting on the articulated arm means increases due to gravity, the upward biasing force of the spring balancer acts to cancel the downward rotational force, As a result, the load on the motor 20 that rotates the first arm 6 is reduced. Therefore, the capacity of the motor 20 can be reduced and control becomes easier, but the most important feature of the present invention is as follows.

That is, according to the present invention, a rotating ring is provided concentrically with the center of rotation of the first arm, and a chain or the like (the chain 72 is used in the embodiment, but a wire, etc. The rotary ring is connected to the pulling rod (rod 68 in the embodiment) of the spring balancer to bias the rotary ring in the same direction as the upward movement direction of the first arm, and the rotary ring is attached to the first arm when the first arm moves downward. (in the embodiment, the long hole 7 of the rotating ring 70
3 is provided, and the rotation range of the rotary ring, which rotates in the same direction with the upward movement of the first arm due to the biasing force of the spring balancer, is set to the vertical movement range of the first arm. It is regulated to a position corresponding to the upper limit position (in the embodiment, it is regulated by one end of the chain guide 71 coming into contact with the swing base 2).

According to this configuration of the present invention, compared to the conventional case where the chain etc. is directly connected to the first arm, a spring balancer with a very common simple structure can be used as it is. Since a spring balancer with a special structure is not required, it can be implemented at low cost. Furthermore, there is no risk of slack in the chain etc. when the first arm rotates within the forward and backward rotation range.

Furthermore, the stroke of the spring balancer's traction rod (piston stroke) only needs to be long enough to correspond to the vertical movement range of the first arm, and there is no need for a stroke to absorb slack in the chain etc. as in the past. Therefore, the total length of the stroke balancer can be configured to be extremely short. Therefore, as shown in the embodiment, the spring balancer can be housed within the rotating base 2, and the base of the robot can be made compact.

Note that the spring balancer may have any configuration. In particular, as shown in the embodiment, the two-stage spring type spring balancer 64 equipped with the auxiliary coil spring 69 that acts at the end of the compression stroke of the main coil spring 66 can exhibit an effective balancer function.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the entire structure, Figure 2 is a longitudinal sectional front view around the pivot base, Figure 3 is a vertical sectional side view around the spring balancer, Figure 4 is a side view of the articulated arm means, and Figure 5 is the same. FIG. 1...Fixed base, 2...Swivel base, 3...
Vertical axis serving as the center of rotation, 4... Joint arm means, 5, 7, 9... Horizontal axis serving as the center of rotation, 6
...First arm, 8...Second arm, 10...Wrist arm, 12...Wrist body, 14...Swivel base drive motor, 15, 28, 40...Gear reducer (harmonic reducer, etc.) ), 20... First arm drive motor, 23, 59, 63... Toothed belt, 24, 60... Gear reduction device, 24a,
60a...Central input shaft, 24b, 60b...Outer fixing ring, 24c, 60c...Ring-shaped output rotating body, 25, 43...Pair of left and right bearings, 26...
... Wrist arm drive motor, 29, 41, 4
7, 50, 56... Rotating shaft, 30, 35, 42,
48...Endless chain, 31...Central bearing part, 34
... Cylinder shaft fixed to second arm, 38 ... Cylinder shaft fixed to wrist arm, 52 ... Wrist main body drive shaft, 55
... Second arm drive motor, 64 ... Spring balancer, 66 ... Main coil spring,
67... Piston, 69... Sub coil spring, 70... Rotating ring, 71... Chain guide, 72... Chain, 73... Long hole, 74... Pin fixed to first arm, R1... No. The longitudinal rotation range of one arm, R2... The vertical rotation range of the first arm.

Claims (1)

[Claims] 1. In an articulated robot having an articulated arm means on a base, the robot continuously rotates in a rotation range that rotates back and forth and a rotation range that rotates up and down around a standing posture. A rotary ring is provided concentrically with the center of rotation of the first arm in the articulated arm means to obtain the rotary ring, and a chain or the like having one end locked to the rotary ring is connected to the pulling rod of the spring balancer to rotate the rotary ring. The first arm is biased in the same direction as the upward movement of the first arm, and the first arm is provided with a pusher that presses and rotates the rotary ring during downward movement, and the urging force of the spring balancer causes the first arm to move upward. An articulated robot comprising a spring balancer that limits the rotation range of the rotary ring that rotates in the same direction as the first arm to a position corresponding to the upper limit position of the vertical movement range of the first arm.